Lactic acid, alkyl esters methyl ester

Lactamide, 81, 71 Lactic acid, alkyl esters, 26, 6 esterification of, 86, 4 methyl ester, 26, 6 polymer of, 86, S... 

Reaction of a metal lactate (such as silver lactate) with an alkyl haUde is a classic method of preparation of the ester, but it is too expensive to be of commercial relevance. Lactamide [2043-43-8] is another high yielding condensation product from lactic acid. It can be produced by aminolysis of dilactide or lactate ester such as methyl or ethyl lactate. 

Enantiomers have identical chemical properties except toward optically active reagents. The two lactic acids are not only acids, but acids of exactly the same strength that is, dissolved in water at the same concentration, bo h ionize to exactly the same degree. The two 2-methyl-1-butanoIs not only form the same products—alkenes on treatment with hot sulfuric acid, alkyl bromides on treatment with HBr, esters on treatment with acetic acid —but also form them at exactly ihe same rate. This is quite reasonable, since the atoms undergoing attack in each case are influenced in their reactivity by exactly the same combination of substituents. The reagent approaching either kind of molecule encounters the same environment, except, of course, that one environment is the mirror image of the other. 

O-Alkyl lactic acid esters are useful reagents for the stereoselective construction of erythro- and t/ireo-a-methyl-a,/3-dihydroxy-esters (Scheme 37). " In the case of (47), R = R = Me, the major product is erythro- (48), but when in (47), R = CH2Ph and R = 2,6-t-butyl-4-methyl, the main product is threo-(49). Yields are excellent, and the stereoselectivity is greater than 97%. Reasonable enantiomeric excesses have been achieved during a study of the Reformatsky and amide base-mediated condensations of chiral acetates with ketones. ... 

Rehberg, C. E. and M. B. Dixon, Mixed Esters of Lactic and Carbonic Acids n-Alkyl Carbonates of Methyl and Butyl Lactates, and Butyl Carbonates of n-Alkyl Lactates. J. Org. Chem., 1950 15, 565-571. 

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